The screw impeller pump is suitable for highly viscous or slightly aggressive liquids. These may include hard and abrasive particles. Due to the resilient material, these particles are pressed against the pump wall and then immediately reabsorbed into the fluid stream. The rotor is helical with two strakes and has a circular diameter. The stator has a helical throughput with two passages as well. When the rotor rotates, the sealed spaces between rotor and stator move. In these enclosed spaces, the medium is carried along in the axial direction of the discharge side.